Reader Louis Schulz recently sent me a link to an incredible set of photos by Eric Valli, a French photographer and former cabinetmaker whose work has taken him all over the world visiting, among other places, the vertiginous and mind-bending world of "honey hunters" in the Himalayas.

However, Louis specifically drew my attention to the visual similarities between the so-called "Shadow Hunters" of underground Thailand and the work of architect Lebbeus Woods.

"In the dark caves of Thailand," Valli explains, "generations of men have risked their lives to obtain a prized commodity-edible bird's nests, essential ingredients of a traditional Chinese soup."

Reaching these nests-found deep within coastal and mountain caves-requires the construction and use of bamboo scaffolding, complicated and rickety architectures of ladders, cranes, attachments, and nearly invisible footholds through which the nest-hunters must paradoxically, in a sense, ascend into the already claustrophobic spaces underground.

Lit only by torchlight, these nests lashed together by humans to reach the nests lashed together by birds are extraordinary and acrobatic constructions, well-compared, I think, to Lebbeus's work, suggesting a unique theatrical stage-set or stadium for seemingly impossible spatial athletics.

Contrast this, for instance, with the farmed equivalent of these wild caves, where bird's nest are basically grown to order inside windowless monoliths, what Nicola Twilley describes as "custom built concrete birds' nest factories... towering above traditional one-story structures and transforming the urban landscape" in Asian cities.

The internal design of these bird's nest farms-or swiftlet hotels, as they are sometimes called-is fascinating: the buildings are intended to mimic caves, with a carefully spaced matrix of wooden rafters replacing the ledges and crannies of a cave ceiling, and detailed attention paid to internal temperature, humidity, and even sound

In any case, how fantastic it would be to see a little pamphlet someday documenting these vernacular structures-subterranean nest-harvesting infrastructures from the mountain caves of Thailand-perhaps something from Princeton Architectural Press or a feature in Domus. See Eric Valli's website for more.